1. Field of the Invention
The present invention relates to a specimen observation method, an image processing device, and a charged-particle beam device. More particularly, it relates to a method and a device which are preferable for observing the same field-of-view as that of a specimen observed using an optical microscope.
2. Description of the Related Art
Concerning a specimen to be observed using an optical microscope, in the case of, e.g., a living-creature specimen, the specimen can be colored by an appropriate staining method which depends on differences in the specimen components and its physiological state. As a result, the specimen can be observed in a state which is close to that of a living body. By the way, in the analysis of living-body reactions like this, fine structure analysis at cell level or macromolecular level is important. An optical microscope, however, finds it difficult to observe the fine structure. This is because the optical microscope has a limitation to its resolving power, and thus can exhibit only an insufficient magnification. Accordingly, for this fine structure analysis to be implemented, the observation made by an electron microscope is desirable.
In JP-A-6-13011, the following explanation has been given: A specimen is observed using an optical image capture device provided independently of an electron microscope. Moreover, its coordinate position and the position of specimen stage of the electron microscope are made to correspond to each other, thereby searching for field-of-view in the electron microscope.
In JP-A-8-129986 (corresponding to U.S. Pat. No. 5,646,403), the following explanation has been given: Regarding field-of-view displacement of a scanning electron microscope, the specimen stage is displaced in correspondence with observation field-of-view width of the scanning electron microscope.
An optical microscope performs formation of a specimen image mainly by detecting reflection light from the specimen. In contrast thereto, however, an electron microscope performs formation of a specimen image by detecting secondary electrons and the like. In this way, since the specimen images are formed based on the different signals, the image qualities are exceedingly different from each other. Consequently, it has been difficult to retrieve the observation field-of-view of the electron microscope on the basis of the specimen image acquired using the optical microscope.